Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Jet-engine, Flame Out?  
User currently offlineD5DBY From , joined Dec 1969, posts, RR:
Posted (8 years 11 months 5 days 22 hours ago) and read 8954 times:

hi

im wondering about if a jet-engine( on a regular jet like MD80, B757) could "stall" and flame out?

ive heard about this...but would an engine flame out if u are flying to slowly..??

like if u are flying at cruise speed and then beginning to stall the AC....would the engine suffer a flame out?

and why is this....beacuse the compressor in the jet-engine dosent get enough air??

17 replies: All unread, jump to last
 
User currently offlineLowrider From United States of America, joined Jun 2004, 3220 posts, RR: 10
Reply 1, posted (8 years 11 months 5 days 22 hours ago) and read 8948 times:

possibly. Check out the Pinnicle crash from late last year. If the airflow is sufficiently disruupted, it can cause the engine to flame out.


Proud OOTSK member
User currently offlineKaddyuk From Wallis and Futuna, joined Nov 2001, 4126 posts, RR: 26
Reply 2, posted (8 years 11 months 5 days 21 hours ago) and read 8921 times:

Quoting D5DBY (Thread starter):
.beacuse the compressor in the jet-engine dosent get enough air??

Yup, just like a wing, the blades of the compressor can also stall, creating a back flow of air in the engine which will stall it  Smile

the problem of "compressor stall." This meant that at certain speeds while in flight, the compressor would pull in more air than the rest of the engine could swallow. Compressor stall produced a sudden blast of air that rushed forward within the engine. The engine lost all its thrust, while this air blast sometimes caused severe damage by breaking off compressor blades.

This also happens in reverse when the engine needs more air than the compressor can supply and it starves the engine of air.



Whoever said "laughter is the best medicine" never had Gonorrhea
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 3, posted (8 years 11 months 5 days 21 hours ago) and read 8911 times:

There is always some confusion outside the industry over use of the word stall.

We talk about stalls in relation to the wings, or more rarely to flight controls.

Unrelated to that we will talk about compressor stalls.

Both of these things have been thoroughly discussed here in the past and a search ought to turn them up.

Problem is, non-aviation people think of their car "stalling" when they hear these things. Our meanings are quite different from that, and very specific.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineFredT From United Kingdom, joined Feb 2002, 2185 posts, RR: 26
Reply 4, posted (8 years 11 months 5 days 21 hours ago) and read 8905 times:

What you need to realize is that compressor/engine stall (or engine surge) is not related to stalling the wing of the aircraft. Wings stall if you exceed a given AoA. Most of the time, this means flying slow. That's not what makes an engine surge.

Engine surges do involve stalling the airfoils of the engine though, as pointed out above.

Short answer, little time...



I thought I was doing good trying to avoid those airport hotels... and look at me now.
User currently offlineAir2gxs From , joined Dec 1969, posts, RR:
Reply 5, posted (8 years 11 months 5 days 19 hours ago) and read 8860 times:

A jet stalling and flaming out are 2 different things. A stall as described above is basically when the airflow through the compressor is disrupted and the engine surges. Flaming out is when the engine basically runs out of fuel. This does not mean it has run dry, it means the fuel control is no longer supplying fuel to the nozzles, for whatever reason.

User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 6, posted (8 years 11 months 5 days 16 hours ago) and read 8807 times:

Quoting Air2gxs (Reply 5):
Flaming out is when the engine basically runs out of fuel. This does not mean it has run dry, it means the fuel control is no longer supplying fuel to the nozzles, for whatever reason.

Wouldn't a stoppage of Aiflow for combustion also be termed as Flame out along with Stoppage of Fuel flow to the Fuel nozzles.As Flame out should mean No Ignition of the Fuel-Air mixture occuring by removal of the sources.
regds
MEL



Think of the brighter side!
User currently offlineFredT From United Kingdom, joined Feb 2002, 2185 posts, RR: 26
Reply 7, posted (8 years 11 months 5 days 9 hours ago) and read 8754 times:

A flame out can happen with the fuel still flowing. It just means that there is no fire in there. A flame-out could well result from an engine surge.

Rapid power increases (which the engine control systems should make impossible), disturbed airflow into the intakes, high altitude, faulty bleed air valves, worn engines... those are the factors increasing the risk for a surge that I can think of off the top of my head,



I thought I was doing good trying to avoid those airport hotels... and look at me now.
User currently offlineAir2gxs From , joined Dec 1969, posts, RR:
Reply 8, posted (8 years 11 months 5 days 8 hours ago) and read 8732 times:

I stand corrected. I was thinking just along the lines of fuel. For some reason (alcohol) my mind seperated airflow from fuel flow.

User currently offlineFredT From United Kingdom, joined Feb 2002, 2185 posts, RR: 26
Reply 9, posted (8 years 11 months 5 days 7 hours ago) and read 8721 times:

Quoting Air2gxs (Reply 8):
I was thinking just along the lines of fuel.

Having a fuel line inside your head does your thinking little good!  Wink



I thought I was doing good trying to avoid those airport hotels... and look at me now.
User currently offlineD5DBY From , joined Dec 1969, posts, RR:
Reply 10, posted (8 years 11 months 5 days 3 hours ago) and read 8674 times:

Quoting Kaddyuk (Reply 2):
the problem of "compressor stall." This meant that at certain speeds while in flight, the compressor would pull in more air than the rest of the engine could swallow.

is this true? dosen´t a engine stall/surge acurs when the compressor blades can´t supply the combustion chamber with enough air?

that the compressor is pulling in to much air..that can´t cause a stall/surge can it?

a stall/surge happens because the compressor can´t supply the combustion chamber with enough air...right?


User currently offlineFredT From United Kingdom, joined Feb 2002, 2185 posts, RR: 26
Reply 11, posted (8 years 11 months 5 days 2 hours ago) and read 8660 times:

D5DBY,
nope, the flow through the engine gets choked, compressorblades stall as the airflow slows down, further breakdown of airflow leads to further stalling of compressorblades and possibly even a complete reversal of flow through the compressor. A huge bang is the result. This can even damage the engine if you are unlucky.

Cheers,
Fred



I thought I was doing good trying to avoid those airport hotels... and look at me now.
User currently offlineKaddyuk From Wallis and Futuna, joined Nov 2001, 4126 posts, RR: 26
Reply 12, posted (8 years 11 months 5 days 1 hour ago) and read 8652 times:

I've tried to find a report but been unlucky...

I CO B742 in the '80s departing from gatwick, suffered a major crosswind which stalled the number one engine completly and affected the number two engine so bad it practically reduced to zero thrust. The aircraft was forced to take off but due to the quick thinking of the flight engineer, it commenced dumping fuel just moments after passing the perimeter fence.

I'd love to read the official report but cant find it...



Whoever said "laughter is the best medicine" never had Gonorrhea
User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3700 posts, RR: 34
Reply 13, posted (8 years 11 months 5 days 1 hour ago) and read 8651 times:
Support Airliners.net - become a First Class Member!

Quoting Kaddyuk (Reply 12):
I CO B742 in the '80s departing from gatwick, suffered a major crosswind which stalled the number one engine completly and affected the number two engine so bad it practically reduced to zero thrust. The aircraft was forced to take off but due to the quick thinking of the flight engineer, it commenced dumping fuel just moments after passing the perimeter fence.

I had to boroscope all the engines on that one.


User currently offlineD5DBY From , joined Dec 1969, posts, RR:
Reply 14, posted (8 years 11 months 5 days 1 hour ago) and read 8644 times:

say if u are about to stall the AC for whatever reason...the pilot realizes this and very fast increase the throttle to max(or close to max) to prevent the AC to stall..

is there a risk that because of this fast increase in throttle, and say that this happens at high altitude (30.000 feet) and perhaps also because the AC is flying "slowly"...( due to the AC stall)

in this specific situation, isen´t there a huge risk that the compressor blades can´t keep up the airflow to the engines.....and by that cause one or 2 engines to stall/surge? ( lets say in this example im talking about a MD80)


User currently offlineKaddyuk From Wallis and Futuna, joined Nov 2001, 4126 posts, RR: 26
Reply 15, posted (8 years 11 months 5 days 1 hour ago) and read 8645 times:

Quoting VC-10 (Reply 13):
I had to boroscope all the engines on that one.

Thats freaky  Wink my instructor when studying Module 15 JAR66 (Gas Turbine Engines) used it to highlight the dangers of compressor stall...!



Whoever said "laughter is the best medicine" never had Gonorrhea
User currently offlineJetlagged From United Kingdom, joined Jan 2005, 2543 posts, RR: 24
Reply 16, posted (8 years 11 months 4 days 19 hours ago) and read 8573 times:

Quoting D5DBY (Reply 14):
say if u are about to stall the AC for whatever reason...the pilot realizes this and very fast increase the throttle to max(or close to max) to prevent the AC to stall..

is there a risk that because of this fast increase in throttle, and say that this happens at high altitude (30.000 feet) and perhaps also because the AC is flying "slowly"...( due to the AC stall)

The engine fuel control unit will limit acceleration (and maybe open bleeds/move stators) to avoid compressor stall.

Quoting D5DBY (Reply 14):
in this specific situation, isen´t there a huge risk that the compressor blades can´t keep up the airflow to the engines.....and by that cause one or 2 engines to stall/surge? ( lets say in this example im talking about a MD80)

With tail mounted engines there is a risk that disturbed airflow from the wings could cause a compressor stall. At the kind of AOA you are at for a wing stall, the wing wake will be well above a typical tail-mounted engine inlet, so no worries there. However you are in much more trouble if the disturbed airflow causes loss of pitch control by affecting the fin mounted horizontal tail (a super-stall).

Why do you think you would be likely to enter a low speed stall condition at 30,000 feet though? Even if this did happen, and both engines flamed out, the pilot could still lower the nose and recover airspeed. From 30,000 feet there would be plenty of time to relight the engines once control was restored.



The glass isn't half empty, or half full, it's twice as big as it needs to be.
User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 17, posted (8 years 11 months 4 days 7 hours ago) and read 8534 times:

Quoting FredT (Reply 11):
A huge bang is the result. This can even damage the engine if you are unlucky

Occurs in R/T mode too.More common.Disapointing to Mx when We hear it.
 Smile

Quoting VC-10 (Reply 13):
I had to boroscope all the engines on that one

Whats the Story behind this Incident.
regds
MEL



Think of the brighter side!
Top Of Page
Forum Index

Reply To This Topic Jet-engine, Flame Out?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Jet Engine Igniter Flame "Source"? posted Wed Sep 26 2001 21:00:30 by Mr spaceman
Please Help Identify This Jet Engine posted Fri Jul 14 2006 23:34:50 by EDDM
Ideal Jet Engine Question? posted Wed Apr 12 2006 03:56:39 by Lehpron
Jet Engine Start Attempt On Running Engine posted Tue Apr 11 2006 01:06:55 by Taguilo
Can It Be Too Cold For A Jet Engine To Operate? posted Mon Jan 23 2006 20:22:26 by Julesmusician
Source Of Noise From A Jet Engine? posted Fri Nov 18 2005 20:58:50 by Lehpron
Jet Engine Windmill On Descent posted Tue Aug 9 2005 21:05:53 by Taguilo
Ionic Jet Engine? posted Sat Jul 9 2005 03:54:08 by Lehpron
Jet Engine That Would Power A Car Sized Plane? posted Wed Mar 16 2005 23:55:05 by UAL747
"Coke Wash" Cleaning Of A Jet Engine? posted Tue Feb 22 2005 18:38:04 by Mr Spaceman
Most Influential Jet Engine Design? posted Sun Apr 3 2011 02:40:06 by faro
Jet Engine Temperature Shock? posted Fri Apr 1 2011 07:45:49 by faro
Olympus "World's Most Efficient Jet Engine"? posted Mon Sep 27 2010 09:04:47 by faro
Jet Engine Heat Usage posted Tue Jul 20 2010 00:34:37 by jetmech
What Is The Cone On The Back Of A Jet Engine? posted Sun May 9 2010 08:55:23 by c5load
Videos For Jet Engine Geeks... posted Mon Mar 29 2010 13:30:56 by JoeCanuck
Simple Quantities For Jet Engine Equations posted Tue Jan 5 2010 13:59:21 by Tboyce12
What Would Make A Jet Engine Get High EGTs? posted Wed Dec 2 2009 23:16:28 by Sovietjet
Which Is The Most Popular Jet Engine Of All Time posted Thu Mar 6 2008 03:31:03 by Clydenairways

Sponsor Message:
Printer friendly format